Streptococcal infections are caused by the Streptococcus group of bacteria and can cause a wide range of illnesses from the common streptococcal pharyngitis (strep throat) to meningitis, pneumonia and necrotising fasciitis. However, many streptococcal species are non-pathogenic, and form part of the normal flora found in the mouth, intestines and upper respiratory tract. Therefore, differentiation in a clinical setting is critical in determining appropriate therapy.